Drainage Inlets

Information listed below is from the FDOTDesign Standards. U.S. Foundry steel grate catalog numbers are for AASHTOH-20 wheel loads, and pedestrian (non-traffic) loading.

Traffic Bearing Inlets

* Inside dimensions are the same for both cast-in-place and precast, except for inlet types J, S, & V which all have precast inside dimensions of 3′–3″ × 3′–10″.
Alt. B structure bottom (FDOT index 200) may be used with inlet types F, G, J, S, & V.
Do not use type J or V inlets where bicycle traffic is anticipated.
Type S inlet is for shoulder gutter applications.

InletType

FDOTIndex

Outside Dimensions

* InsideDimensions

Max. Pipe Size

Steel Grate #

Cast-In-Place

Precast

Short

Long

H-20

Non-Traf

F

233

3′–10″ × 5′–4″

3′–6″ × 5′–0″

2′–6″ × 4′–0″

18″

30″

6631

6630

G

6′–2″ × 6′–4″

4′–10″ × 5′–0″

42″

6661

6660

J

234

4′–3″ × 5′–4″

4′–3″ × 4′–10″

2′–11″ × 4′–0″

24″

30″

6685

6652

S

220

6658

6652

V

221

6657

6651

Non-Traffic Bearing Inlets

* 18″ maximum where an 18″ pipe enters a 2′–0″ wall.
Inside dimensions are the same for both cast-in-place and precast.
Alt. B structure bottom (FDOT index 200) may be used with inlet types C, D, & E.
H(2) is type H inlet with 2 steel grates; H(4) is type H inlet with 4 steel grates.Note: Although H-20 steel grate catalog numbers are listed for non-traffic bearing inlets, the use of these inlets in areas subject to heavy wheel loads is strongly discouraged.

InletType

FDOTIndex

Outside Dimensions

InsideDimensions

Max. Pipe Size

Steel Grate #

Cast-In-Place

Precast

Short

Long

H-20

Non-Traf

C

232

3′–4″ × 4′–5″

3′–0″ × 4′–1″

2′–0″ × 3′–1″

18″

* 24″

6611

6606

D

4′–5″ × 5′–5″

4′–1″ × 5′–1″

3′–1″ × 4′–1″

24″

36″

6626

6607

E

4′–4″ × 5′–10″

4′–0″ × 5′–6″

3′–0″ × 4′–6″

6616

6608

H(2)

4′–4″ × 7′–11″

4′–0″ × 7′–7″

3′–0″ × 6′–7″

60″ or2–24″

6621

6609

H(4)

4′–4″ × 10′–1″

4′–0″ × 9′–9″

3′–0″ × 8′–9″

78″ or2–30″

?

?

Curb Inlets

* Hydraulic intake values do not represent hydraulic capacity, but are shown to compare inlets based on a 0.2% longitudinal slope, 2% cross slope, and a 90% efficiency factor.